Catheter pump with access ports

ABSTRACT

A catheter pump is disclosed herein. The catheter pump can include an elongate catheter body and an impeller assembly coupled to a distal portion of the elongate catheter body. The impeller assembly can comprise an impeller configured to rotate during operation of the catheter pump. A tube can extend through at least portions of the elongate catheter body and the impeller assembly. The tube can extend distal the impeller and can be configured to remain in the portions of the elongate catheter body and the impeller assembly during operation of the catheter pump.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/979,952, filed Apr. 15, 2014, the contents of which areincorporated by reference herein in their entirety and for all purposes.

BACKGROUND OF THE INVENTION

Field of the Invention

This application is directed to catheter pumps for mechanicalcirculatory support of a heart.

Description of the Related Art

Heart disease is a major health problem that has high mortality rate.Physicians increasingly use mechanical circulatory support systems fortreating heart failure. The treatment of acute heart failure requires adevice that can provide support to the patient quickly. Physiciansdesire treatment options that can be deployed quickly andminimally-invasively.

Intra-aortic balloon pumps (IABP) are currently the most common type ofcirculatory support devices for treating acute heart failure. IABPs arecommonly used to treat heart failure, such as to stabilize a patientafter cardiogenic shock, during treatment of acute myocardial infarction(MI) or decompensated heart failure, or to support a patient during highrisk percutaneous coronary intervention (PCI). Circulatory supportsystems may be used alone or with pharmacological treatment.

In a conventional approach, an IABP is positioned in the aorta andactuated in a counterpulsation fashion to provide partial support to thecirculatory system. More recently minimally-invasive rotary blood pumphave been developed in an attempt to increase the level of potentialsupport (i.e., higher flow). A rotary blood pump is typically insertedinto the body and connected to the cardiovascular system, for example,to the left ventricle and the ascending aorta to assist the pumpingfunction of the heart. Other known applications pumping venous bloodfrom the right ventricle to the pulmonary artery for support of theright side of the heart. An aim of acute circulatory support devices isto reduce the load on the heart muscle for a period of time, tostabilize the patient prior to heart transplant or for continuingsupport.

There is a need for improved mechanical circulatory support devices fortreating acute heart failure. Fixed cross-section ventricular assistdevices designed to provide near full heart flow rate are either toolarge to be advanced percutaneously (e.g., through the femoral arterywithout a cutdown) or provide insufficient flow.

There is a need for a pump with improved performance and clinicaloutcomes. There is a need for a pump that can provide elevated flowrates with reduced risk of hemolysis and thrombosis. There is a need fora pump that can be inserted minimally-invasively and provide sufficientflow rates for various indications while reducing the risk of majoradverse events. In one aspect, there is a need for a heart pump that canbe placed minimally-invasively, for example, through a 15FR or 12FRincision. In one aspect, there is a need for a heart pump that canprovide an average flow rate of 4 Lpm or more during operation, forexample, at 62 mmHg of head pressure. While the flow rate of a rotarypump can be increased by rotating the impeller faster, higher rotationalspeeds are known to increase the risk of hemolysis, which can lead toadverse outcomes and in some cases death. Accordingly, in one aspect,there is a need for a pump that can provide sufficient flow atsignificantly reduced rotational speeds. These and other problems areovercome by the inventions described herein.

Further, there is a need for a motor configured to drive an operativedevice, e.g., a impeller, at a distal portion of the pump. It can beimportant for the motor to be configured to allow for percutaneousinsertion of the pump's operative device.

SUMMARY OF THE INVENTION

There is an urgent need for a pumping device that can be insertedpercutaneously and also provide full cardiac rate flows of the left,right, or both the left and right sides of the heart when called for.

In one embodiment, a catheter pump is disclosed. The catheter pump cancomprise an elongate catheter body. An impeller assembly can be coupledto a distal portion of the elongate catheter body. The impeller assemblycan comprise an impeller configured to rotate during operation of thecatheter pump. The catheter pump can comprise an access channelextending through at least portions of the elongate catheter body andthe impeller assembly. The access channel can extend distal the impellerand configured to remain in the portions of the elongate catheter bodyand the impeller assembly during operation of the catheter pump.

In another embodiment, a method of operating a catheter pump isdisclosed. The method can comprise advancing a guidewire to a treatmentlocation in a patient. The method can include disposing a distal end ofa guidewire guide tube over the guidewire. The guidewire guide tube canbe disposed in a catheter pump comprising a catheter body and animpeller assembly coupled to a distal portion of the catheter body. Themethod can comprise advancing the impeller assembly, the catheter body,and the guidewire guide tube along the guidewire to position theimpeller assembly at the treatment location. The method can includeactivating the impeller assembly to pump blood while maintaining theguidewire guide tube in the catheter pump.

In one embodiment, a catheter pump is disclosed. The catheter pump caninclude a catheter assembly. The catheter assembly can include a driveshaft having a proximal end and a distal end. An impeller may be coupledwith the distal end of the drive shaft. A driven magnet assembly may becoupled with the proximal end of the drive shaft. The driven magnetassembly can include a driven magnet housing having a driven magnet. Thecatheter pump can further include a drive system. The drive system caninclude a motor having an output shaft. The drive system can alsoinclude a drive magnet assembly coupled with the output shaft. The drivemagnet assembly can include a drive magnet housing with a drive magnetdisposed therein. A securement device can be configured to secure thedriven magnet housing into engagement with the drive magnet housingduring operation of the pump.

In another embodiment, a catheter pump is disclosed. The catheter pumpcan include a catheter assembly. The catheter assembly can comprise adrive shaft having a proximal end and a distal end. An impeller can becoupled with the distal end of the drive shaft. A rotatable magnet canbe coupled with the proximal end. The rotatable magnet can be disposedin a driven magnet housing. Furthermore, the catheter pump can include adrive system comprising a plurality of motor windings configured toinduce rotation of the rotatable magnet when the driven magnet housingis engaged with the drive system. A locking device can be configured tobe engaged by insertion of the driven magnet housing into an opening ofthe drive system.

In yet another embodiment, a method is disclosed. The method can includeinserting a proximal portion of a catheter assembly containing a magnetinto a recess of a drive unit. The method can further include engaging alocking device to secure the proximal portion of the catheter assemblyto the drive unit.

In another embodiment, a catheter assembly is disclosed. The catheterassembly can include a catheter body having a proximal portion and adistal portion. An operative device can be coupled to the distal portionof the catheter body. A tip member can be coupled to a distal portion ofthe operative device. The tip member can have a lumen comprising a firstsection and a second section connected to the first section. An innerdiameter of the first section can be larger than an inner diameter ofthe second section.

In one embodiment, a catheter pump is provided that includes a catheterassembly and a drive system, and a securement device. The catheterassembly includes a drive shaft, an impeller, and a driven assembly. Thedrive shaft has a proximal end and a distal end. The impeller is coupledwith the distal end of the drive shaft. The driven assembly may becoupled with the proximal end of the drive shaft, the driven assembly isdisposed in a driven housing. The drive system includes a motor havingan output shaft and a output drive assembly coupled with the shaft. Thedrive assembly includes a drive housing with at least one magnetdisposed therein. The securement device is configured to preventdisengagement of the driven housing from the drive housing duringoperation of the pump.

In one embodiment, a catheter pump is provided that includes a catheterassembly and a drive system, and a damper. The catheter assemblyincludes a drive shaft, an impeller, and a driven member. The driveshaft has a proximal end and a distal end. The impeller is coupled withthe distal end of the drive shaft. The driven member is coupled with theproximal end of the drive shaft. The drive system includes a motorhaving an output shaft and a drive member coupled with the output shaft.

In one variant, the catheter pump can have a damper disposed between thedrive and driven member. The damper can be configured to isolate thedrive member or the motor from vibration in the catheter assembly. Thedamper can be configured to suppress noise at or around the connectionbetween the drive and drive members.

Preferably, the damper is disposed radially around the output shaft,e.g., completely surrounding the output shaft. The damper can bedisposed between separable housings of the catheter assembly and drivesystem, e.g., abutting a distal face of a drive system housing and aproximal face of a driven member housing disposed on the proximal end ofthe catheter assembly.

This embodiment can be augmented in some embodiments with adisconnectable coupling between the drive and driven members. Forexample, a securement device can be configured to permit selectivedisengagement of these components from each other. The securement devicecan be configured to prevent disengagement of the driven housing fromthe drive housing during operation of the pump.

Connection of the drive and driven members can be by the mutualattraction of opposing poles of permanent magnets disposed therein.Alternatively, the driven member can be positioned to be acted uponmagnetic fields generated in the winding, e.g., using commutation in thewindings. In another embodiment, the drive and driven members arecoupled using direct mechanical drive, such as with gears, splines orother abutting surfaces.

In another embodiment, a catheter pump is provided that has a catheterassembly, a drive system, and a locking device. The catheter assemblyhas a drive shaft that has a proximal end and a distal end. An impelleris coupled with the distal end of the drive shaft. A rotatable magnet iscoupled with the proximal end of the drive shaft. The rotatable magnetis disposed in a driven magnet housing. The drive system has a pluralityof motor windings configured to induce rotation of the rotatable magnetafter the driven magnet housing is engaged with the drive system. Thelocking device is configured to be engaged by insertion of the drivenmagnet housing into a portion or recess of the drive system.

Rotation can be induced in the rotatable magnet by the mutual attractionof opposing poles of permanent magnets. The rotatable magnet can be anassembly having one or a first plurality of permanent magnets and one ora second plurality of permanent magnets can be mounted on a shaft of themotor having the motor windings. Pairing of opposite poles of twomagnets or of the magnets of the first and second pluralities ofpermanent magnets can induce rotation that can be transferred to thedrive shaft. Alternatively, the rotatable magnet can be positioned to beacted upon magnetic fields generated in the winding, e.g., usingcommutation in the windings.

In another embodiment, a method is provided. A proximal portion of acatheter assembly containing a magnet is inserted into a recess of adrive unit. A locking device is engaged to secure the proximal portionof the catheter assembly to a distal portion of the drive unit.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of this applicationand the various advantages thereof can be realized by reference to thefollowing detailed description, in which reference is made to theaccompanying drawings in which:

FIG. 1 illustrates one embodiment of a catheter pump configured forpercutaneous application and operation;

FIG. 2 is a plan view of one embodiment of a catheter adapted to be usedwith the catheter pump of FIG. 1;

FIG. 3 show a distal portion of the catheter system similar to that ofFIG. 2 in position within the anatomy;

FIG. 4 is a schematic view of a catheter assembly and a drive assembly;

FIG. 4A is an enlarged view of a priming apparatus shown in FIG. 4;

FIG. 5 is a three dimensional (3D) perspective view of a motor assemblyas the drive assembly is being coupled to a driven assembly;

FIG. 6 is a 3D perspective view of the motor assembly once the driveassembly has been coupled and secured to the driven assembly;

FIG. 7 is a 3D perspective view of the motor assembly of FIG. 6, whereinvarious components have been removed for ease of illustration;

FIG. 8 is a plan view of the motor assembly that illustrates a motor, adrive magnet and a driven magnet;

FIG. 9 is a 3D perspective view of a first securement device configuredto secure the drive assembly to the driven assembly;

FIGS. 10A-10C are 3D perspective views of a second securement deviceconfigured to secure the drive assembly to the driven assembly;

FIG. 11 illustrates a side schematic view of a motor assembly accordingto another embodiment;

FIGS. 12A-12B illustrates side schematic views of a motor assemblyaccording to yet another embodiment;

FIG. 13 is a side view of a distal tip member disposed at a distal endof the catheter assembly, according to one embodiment;

FIG. 14 is a side cross-sectional view of a distal tip member disposedat a distal end of the catheter assembly, according to anotherembodiment.

FIG. 15 is a side view of an impeller assembly having a cannula housing,an impeller disposed in the cannula housing, and a tip member, accordingto various embodiments.

FIG. 16 is a side cross-sectional view of an access channel disposed ata distal end of the catheter assembly, according to another embodiment.

FIGS. 17A and 17B are images of a proximal portion of an access channel,according to some embodiments.

More detailed descriptions of various embodiments of components forheart pumps useful to treat patients experiencing cardiac stress,including acute heart failure, are set forth below.

DETAILED DESCRIPTION I. Overview of System Components

This application is directed to apparatuses for inducing motion of afluid relative to the apparatus. For example, an operative device, suchas an impeller, can be coupled at a distal portion of the apparatus. Inparticular, the disclosed embodiments generally relate to variousconfigurations for a motor adapted to drive an impeller at a distal endof a catheter pump, e.g., a percutaneous heart pump. The disclosed motorassembly may be disposed outside the patient in some embodiments. Inother embodiments, the disclosed motor assembly can be miniaturized andsized to be inserted within the body. FIGS. 1-3 show aspects of acatheter pump 10 that can provide high performance flow rates. The pump10 includes a motor driven by a controller 22. The controller 22 directsthe operation of the motor 14 and an infusion or operating fluid system26 that supplies a flow of operating fluid or infusate in the pump 10.

A catheter system 80 that can be coupled with the motor 14 houses animpeller within a distal portion thereof. In various embodiments, theimpeller is rotated remotely by the motor 14 when the pump 10 isoperating. For example, the motor 14 can be disposed outside thepatient. In some embodiments, the motor 14 is separate from thecontroller 22, e.g., to be placed closer to the patient. In otherembodiments, the motor 14 is part of the controller 22. In still otherembodiments, the motor is miniaturized to be insertable into thepatient. Such embodiments allow a drive shaft conveying torque to animpeller or other operating element at the distal end to be muchshorter, e.g., shorter than the distance from the aortic valve to theaortic arch (about 5 cm or less). Some examples of miniaturized motorscatheter pumps and related components and methods are discussed in U.S.Pat. No. 5,964,694; U.S. Pat. No. 6,007,478; U.S. Pat. No. 6,178,922;and U.S. Pat. No. 6,176,848, all of which are hereby incorporated byreference herein in their entirety for all purposes. Various embodimentsof a motor are disclosed herein, including embodiments having separatedrive and driven assemblies to enable the use of a guidewire guidepassing through the catheter pump. As explained herein, a guidewireguide can facilitate passing a guidewire through the catheter pump forpercutaneous delivery of the pump's operative device to a patient'sheart.

In some embodiments, the guidewire guide can be removable from thepatient once the catheter pump is positioned in the anatomy. In otherembodiments, the guidewire guide can be configured as an access port oraccess channel to provide access to the heart while the impeller isrotating. For example, the access channel or guidewire guide may bepermanently or non-removably disposed in the catheter pump such that theguidewire guide remains in the catheter pump during operation. In otherarrangements, the guidewire guide can remain in the catheter pump andpatient during operation but can be removed by the clinician whendesired. Providing such an access channel (e.g., a guidewire guide) canenable the clinician to have access to the heart during the procedurefor various purposes. For example, one or more sensors can be disposedthrough the access channel to measure fluid properties during theprocedure. Medications or other chemicals may be delivered through theaccess channel during the procedure. Furthermore, the use of a guidewireguide that remains in the patient during treatment can enable theclinician to reinsert the guidewire to reposition the catheter pump ifthe catheter pump becomes misaligned during the procedure. It should beappreciated that, although the guidewire guide may be described aspermanent or non-removable in various embodiments, this is meant todesignate a guidewire guide that is configured to remain in the catheterpump during operation of the catheter pump, even if the guidewire guideis physically capable of being removed from the catheter pump, e.g., bydisassembly of the catheter pump and/or by suitable forces being appliedto the guidewire guide. Indeed, in various embodiments, the accesschannel or guidewire guide is configured to be removed from the catheterpump when desired by the clinician.

FIGS. 1-4 show aspects of one embodiment of a catheter pump 10 that canprovide high performance flow rates. Various additional aspects of thepump and associated components are similar to those disclosed in U.S.Pat. Nos. 7,393,181, 8,376,707, 7,841,976, 8,535,211, 8,597,170,8,485,961, 8,591,393, 7,022,100, and 7,998,054 and U.S. Pub. Nos.2012/0178986, 2013/0303970, 2013/0303969, 2013/0303830, 2014/0012065,and 2014/0010686 the entire contents of which are incorporated hereinfor all purposes by reference. In addition, this applicationincorporates by reference in its entirety and for all purposes thesubject matter disclosed in each of the following concurrently filedapplications: U.S. patent application Ser. No. 14/203,978 (US2014/0275725), entitled “FLUID HANDLING SYSTEM,” and Ser. No. 14/209,889(US 2014/0275726), entitled “CATHETER PUMP ASSEMBLY INCLUDING A STATOR,”filed on Mar. 13, 2014 and PCT Patent Application Nos. PCT/US2014/020790(WO 2014/164136), entitled “FLUID HANDLING SYSTEM,” andPCT/US2014/020878 (WO 2014/143593), entitled “CATHETER PUMP ASSEMBLYINCLUDING A STATOR,” filed on Mar. 5, 2014.

FIG. 3 illustrates one use of the catheter pump 10. A distal portion ofthe pump 10, which can include an impeller assembly 92, is placed in theleft ventricle LV of the heart to pump blood from the LV into the aorta.The pump 10 can be used in this way to treat patients with a wide rangeof conditions, including cardiogenic shock, myocardial infarction, andother cardiac conditions, and also to support a patient during aprocedure such as percutaneous coronary intervention. One convenientmanner of placement of the distal portion of the pump 10 in the heart isby percutaneous access and delivery using the Seldinger technique orother methods familiar to cardiologists. These approaches enable thepump 10 to be used in emergency medicine, a catheter lab and in othernon-surgical settings. Modifications can also enable the pump 10 tosupport the right side of the heart. Example modifications that could beused for right side support include providing delivery features and/orshaping a distal portion that is to be placed through at least one heartvalve from the venous side, such as is discussed in U.S. Pat. No.6,544,216; U.S. Pat. No. 7,070,555; and US 2012-0203056A1, all of whichare hereby incorporated by reference herein in their entirety for allpurposes.

FIG. 2 shows features that facilitate small blood vessel percutaneousdelivery and high performance, including up to and in some casesexceeding normal cardiac output in all phases of the cardiac cycle. Inparticular, the catheter system 80 includes a catheter body 84 and asheath assembly 88. The catheter body 84 can include an elongate bodywith proximal and distal end, in which a length of the body 84 enablesthe pump 10 to be applied to a patient from a peripheral vascularlocation. The impeller assembly 92 is coupled with the distal end of thecatheter body 84. The impeller assembly 92 is expandable andcollapsible. In the collapsed state, the distal end of the cathetersystem 80 can be advanced to the heart, for example, through an artery.In the expanded state the impeller assembly 92 is able to pump blood athigh flow rates. FIGS. 2 and 3 illustrate the expanded state. Thecollapsed state can be provided by advancing a distal end 94 of anelongate body 96 distally over the impeller assembly 92 to cause theimpeller assembly 92 to collapse. This provides an outer profilethroughout the catheter assembly 80 that is of small diameter, forexample, to a catheter size of about 12.5 FR in various arrangements.

In some embodiments, the impeller assembly 92 includes a self-expandingmaterial that facilitates expansion. The catheter body 84 on the otherhand preferably is a polymeric body that has high flexibility.

The mechanical components rotatably supporting the impeller within theimpeller assembly 92 permit high rotational speeds while controllingheat and particle generation that can come with high speeds. Theinfusion system 26 delivers a cooling and lubricating solution(sometimes referred to herein as an operating fluid) to the distalportion of the catheter system 80 for these purposes. However, the spacefor delivery of this fluid is extremely limited. Some of the space isalso used for return of the operating fluid. Providing secure connectionand reliable routing of operating fluid into and out of the catheterassembly 80 is critical and challenging in view of the small profile ofthe catheter body 84.

When activated, the catheter pump system can effectively increase theflow of blood out of the heart and through the patient's vascularsystem. In various embodiments disclosed herein, the pump can beconfigured to produce a maximum flow rate (e.g. low mm Hg) of greaterthan 4 Lpm, greater than 4.5 Lpm, greater than 5 Lpm, greater than 5.5Lpm, greater than 6 Lpm, greater than 6.5 Lpm, greater than 7 Lpm,greater than 7.5 Lpm, greater than 8 Lpm, greater than 9 Lpm, or greaterthan 10 Lpm. In various embodiments, the pump can be configured toproduce an average flow rate at 62 mmHg of greater than 2 Lpm, greaterthan 2.5 Lpm, greater than 3 Lpm, greater than 3.5 Lpm, greater than 4Lpm, greater than 4.25 Lpm, greater than 4.5 Lpm, greater than 5 Lpm,greater than 5.5 Lpm, or greater than 6 Lpm.

Another example of a catheter assembly 100A is illustrated in FIG. 4.Embodiments of the catheter pump of this application can be configuredwith a motor that is capable of coupling to (and in some arrangementsoptionally decoupling from) the catheter assembly 100A. This arrangementprovides a number of advantages over a non-disconnectable motor. Forexample, access can be provided to a proximal end of the catheterassembly 100A prior to or during use. In one configuration, a catheterpump is delivered over a guidewire. The guidewire may be convenientlyextended through the entire length of the catheter assembly 100A and outof a proximal portion thereof that is completely enclosed in a coupledconfiguration. For this approach, connection of the proximal portion ofthe catheter assembly 100A to a motor housing can be completed after aguidewire has been used to guide the operative device of the catheterpump to a desired location within the patient, e.g., to a chamber of thepatient's heart. In one embodiment, the connection between the motorhousing and the catheter assembly is configured to be permanent, suchthat the catheter assembly, the motor housing and the motor aredisposable components. However, in other implementations, the couplingbetween the motor housing and the catheter assembly is disengageable,such that the motor and motor housing can be decoupled from the catheterassembly after use. In such embodiments, the catheter assembly distal ofthe motor can be disposable, and the motor and motor housing can bere-usable.

Moving from the distal end of the catheter assembly 100A of FIG. 4 tothe proximal end, a priming apparatus 1400 can be disposed over animpeller assembly 116A. As explained above, the impeller assembly 116Acan include an expandable cannula or housing and an impeller with one ormore blades. As the impeller rotates, blood can be pumped proximally (ordistally in some implementations) to function as a cardiac assistdevice.

FIG. 4 also shows one example of a priming apparatus 1400 disposed overthe impeller assembly 116A near the distal end 170A of the elongate body174A. FIG. 4A is an enlarged view of the priming apparatus 1400 shown inFIG. 4. The priming apparatus 1400 can be used in connection with aprocedure to expel air from the impeller assembly 116A, e.g., any airthat is trapped within the housing or that remains within the elongatebody 174A near the distal end 170A. For example, the priming proceduremay be performed before the pump is inserted into the patient's vascularsystem, so that air bubbles are not allowed to enter and/or injure thepatient. The priming apparatus 1400 can include a primer housing 1401configured to be disposed around both the elongate body 174A and theimpeller assembly 116A. A sealing cap 1406 can be applied to theproximal end 1402 of the primer housing 1401 to substantially seal thepriming apparatus 1400 for priming, i.e., so that air does notproximally enter the elongate body 174A and also so that priming fluiddoes not flow out of the proximal end of the housing 1401. The sealingcap 1406 can couple to the primer housing 1401 in any way known to askilled artisan. However, in some embodiments, the sealing cap 1406 isthreaded onto the primer housing by way of a threaded connector 1405located at the proximal end 1402 of the primer housing 1401. The sealingcap 1406 can include a sealing recess disposed at the distal end of thesealing cap 1406. The sealing recess can be configured to allow theelongate body 174A to pass through the sealing cap 1406.

The priming operation can proceed by introducing fluid into the sealedpriming apparatus 1400 to expel air from the impeller assembly 116A andthe elongate body 174A. Fluid can be introduced into the primingapparatus 1400 in a variety of ways. For example, fluid can beintroduced distally through the elongate body 174A into the primingapparatus 1400. In other embodiments, an inlet, such as a luer, canoptionally be formed on a side of the primer housing 1401 to allow forintroduction of fluid into the priming apparatus 1400.

A gas permeable membrane can be disposed on a distal end 1404 of theprimer housing 1401. The gas permeable membrane can permit air to escapefrom the primer housing 1401 during priming.

The priming apparatus 1400 also can advantageously be configured tocollapse an expandable portion of the catheter assembly 100A. The primerhousing 1401 can include a funnel 1415 where the inner diameter of thehousing decreases from distal to proximal. The funnel may be gentlycurved such that relative proximal movement of an impeller housing ofthe impeller assembly 116A causes the impeller housing to be collapsedby the funnel 1415. During or after the impeller housing has been fullycollapsed, the distal end 170A of the elongate body 174A can be moveddistally relative to the collapsed housing. After the impeller housingis fully collapsed and retracted into the elongate body 174A of thesheath assembly, the catheter assembly 100A can be removed from thepriming housing 1400 before a percutaneous heart procedure is performed,e.g., before the pump is activated to pump blood. The embodimentsdisclosed herein may be implemented such that the total time forinfusing the system is minimized or reduced. For example, in someimplementations, the time to fully infuse the system can be about sixminutes or less. In other implementations, the time to infuse can beabout three minutes or less. In yet other implementations, the totaltime to infuse the system can be about 45 seconds or less. It should beappreciated that lower times to infuse can be advantageous for use withcardiovascular patients.

With continued reference to FIG. 4, the elongate body 174A extendsproximally from the impeller assembly 116A to an infusate device 195configured to allow for infusate to enter the catheter assembly 100A andfor waste fluid to leave the catheter assembly 100A. A catheter body120A (which also passes through the elongate body 174A) can extendproximally and couple to a driven assembly 201. The driven assembly 201can be configured to receive torque applied by a drive assembly 203,which is shown as being decoupled from the driven assembly 201 and thecatheter assembly 100A in FIG. 4. Although not shown in FIG. 4, a driveshaft can extend from the driven assembly 201 through the catheter body120A to couple to an impeller shaft at or proximal to the impellerassembly 116A. The catheter body 120A can pass within the elongatecatheter body 174A such that the external catheter body 174A can axiallytranslate relative to the catheter body 120A.

In addition, FIG. 4 illustrates a guidewire 235 extending from aproximal guidewire opening 237 in the driven assembly 201. Beforeinserting the catheter assembly 100A into a patient, a clinician mayinsert the guidewire 235 through the patient's vascular system to theheart to prepare a path for the operative device (e.g., the impellerassembly 116A) to the heart. In some embodiments, the catheter assemblycan include a guidewire guide tube (see FIG. 12) passing through acentral internal lumen of the catheter assembly 100A from the proximalguidewire opening 237. The guidewire guide tube can be pre-installed inthe catheter assembly 100A to provide the clinician with a preformedpathway along which to insert the guidewire 235.

In one approach, a guidewire is first placed in a conventional way,e.g., through a needle into a peripheral blood vessel, and along thepath between that blood vessel and the heart and into a heart chamber,e.g., into the left ventricle. Thereafter, a distal end opening of thecatheter assembly 100A or guidewire guide can be advanced over theproximal end of the guidewire 235 to enable delivery to the catheterassembly 100A. After the proximal end of the guidewire 235 is urgedproximally within the catheter assembly 100A and emerges from theguidewire opening 237 and/or guidewire guide, the catheter assembly 100Acan be advanced into the patient. In one method, the guidewire guide iswithdrawn proximally while holding the catheter assembly 100A. Theguidewire guide is taken off of the catheter assembly 100A so thatguidewire lumens from the proximal end to the distal end of the catheterassembly 100A are directly over the guidewire. In other embodiments, asexplained in more detail below, the guidewire guide may be coupled withthe catheter assembly 100A such that the guidewire guide is not removedduring operation of the catheter pump. In such arrangements, theguidewire guide can act as an access channel to the anatomy.

Alternatively, the clinician can thus insert the guidewire 235 throughthe proximal guidewire opening 237 and urge the guidewire 235 along theguidewire guide tube until the guidewire 235 extends from a distalguidewire opening (not shown) in the distal end of the catheter assembly100A. The clinician can continue urging the guidewire 235 through thepatient's vascular system until the distal end of the guidewire 235 ispositioned in the desired chamber of the patient's heart. As shown inFIG. 4, a proximal end portion of the guidewire 235 can extend from theproximal guidewire opening 237. Once the distal end of the guidewire 235is positioned in the heart, the clinician can maneuver the impellerassembly 116A over the guidewire 235 until the impeller assembly 116Areaches the distal end of the guidewire 235 in the heart. The cliniciancan remove the guidewire 235 and the guidewire guide tube. The guidewireguide tube can also be removed before or after the guidewire 235 isremoved in some implementations. In other embodiments, as explainedbelow, the guidewire guide tube may remain within the catheter assembly100A during the treatment procedure.

After removing at least the guidewire 235, the clinician can activate amotor to rotate the impeller and begin operation of the pump.

One problem that arises when using the guidewire 235 to guide theoperative device to the heart is that a central lumen or tube (e.g., aguidewire guide) is typically formed to provide a path for the guidewire235. In some implementations, it may be inconvenient or inoperable toprovide a motor or drive assembly having a lumen through which theguidewire 235 can pass. Moreover, in some implementations, it may bedesirable to provide the motor or drive assembly separate from thecatheter assembly 100A, e.g., for manufacturing or economic purposes.Thus, it can be advantageous to provide a means to couple the driveassembly 203 to the driven assembly 201, while enabling the use of aguidewire guide through which a guidewire may be passed. Preferably, thedrive assembly 203 can be securely coupled to the driven assembly 201such that vibratory, axial, or other external forces do not decouple thedrive assembly 203 from the driven assembly 201 during operation.Moreover, the coupling should preferably allow a motor to operateeffectively so that the drive shaft is rotated at the desired speed andwith the desired torque.

II. Examples of Motor Assemblies

FIG. 5 illustrates one embodiment of a motor assembly 206 as the drivenassembly 201 is being coupled to the drive assembly 203. The drivenassembly 201 can include a flow diverter 205 and a flow diverter housing207 that houses the flow diverter 205. The flow diverter 205 can beconfigured with a plurality of internal cavities, passages, and channelsthat are configured to route fluid to and from the patient during amedical procedure. As discussed below, an infusate can be directed intothe flow diverter from a source of infusate. The infusate is a fluidthat flows into the catheter body 120A to provide useful benefits, suchas cooling moving parts and keeping blood from entering certain parts ofthe catheter assembly 100A. The infusate is diverted distally by flowchannels in the flow diverter 205. Some of the infusate that flowsdistally is re-routed back through the catheter body 120A and may bediverted out of the catheter assembly 100A by the flow diverter 205.Moreover, a driven magnet 204 can be disposed within the flow diverter205 in various embodiments. For example, the driven magnet 204 can bejournaled for rotation in a proximal portion of the flow diverterhousing 207. The proximal portion can project proximally of a proximalface of a distal portion of the flow diverter housing 207. In otherembodiments, the driven magnet 204 can be disposed outside the flowdiverter 205. The driven magnet 204 can be configured to rotate freelyrelative to the flow diverter 205 and/or the flow diverter housing 207.The catheter body 120A can extend from a distal end of the flow diverterhousing 207. Further, a drive shaft 208 can pass through the catheterbody 120A from the proximal end of the flow diverter housing 207 to thedistal end 170A of the elongate body 174A. The drive shaft 208 can beconfigured to drive the impeller located at the distal end of thecatheter assembly 100A. In some embodiments, a distal end of the driveshaft 208 can couple to an impeller shaft, which rotates the impeller.

The drive assembly 203 can include a drive housing or a motor housing211 having an opening 202 in a cap 212 of the motor housing 211. Themotor housing 211 can also have a sliding member 213, which can beconfigured to couple to the patient's body by way of, e.g., a connector291 coupled to an adhesive or bandage on the patient's body. Because themotor and motor housing 211 can have a relatively high mass, it can beimportant to ensure that the motor housing 211 is stably supported. Inone implementation, therefore, the motor housing 211 can be supported bythe patient's body by way of the sliding member 213 and the connector291 shown in FIG. 4. The sliding member 213 can slide along a track 214located on a portion of the motor housing 211, such that relative motionbetween the motor assembly 206 and the patient does not decouple thesliding member 213 from the patient's body. The sliding member 213 andconnector 291 can therefore be configured to provide a structuralinterface between the motor housing 206 and a platform for supportingthe motor housing 211. As explained above, in some arrangements, theplatform supporting the motor housing 211 can be the patient, since themotor housing 211 may be positioned quite close to the insertion point.In other arrangements, however, the platform supporting the motorhousing 211 may be an external structure.

To couple the drive assembly 203 to the driven assembly 201, theclinician or user can insert the proximal portion of the flow diverter205 into the opening 202 in the cap 212 of the motor housing 212. Afterpassing through the opening 202, the proximal portion of the flowdiverter can reside within a recess formed within the motor housing 211.In some implementations, a securement device is configured to lock orsecure the drive assembly 203 to the driven assembly 201 once the drivenassembly 201 is fully inserted into the drive assembly 203. In otherimplementations, the securement device can be configured to secure thedrive assembly 203 to the driven assembly 201 by inserting the drivenassembly 201 into the drive assembly 203 and then rotating the driveassembly 203 with respect to the driven assembly 201. In someimplementations, coupling the drive assembly 203 to the driven assembly201 may be irreversible, such that there may be no release mechanism todecouple the drive assembly 203 from the driven assembly 201. Inimplementations without a release mechanism, the catheter assembly 100A(including the driven assembly 201) and the motor housing 211 may bedisposable components. In other implementations, however, a releasemechanism may be provided to remove the drive assembly 203 from thedriven assembly 201. The drive assembly 203 can thereby be used multipletimes in some embodiments.

FIG. 6 illustrates the motor assembly 206 in the assembled state, e.g.,after the drive assembly 203 has been secured to the driven assembly201. When the drive assembly 203 is activated (e.g., a motor isactivated to rotate an output shaft), the driven assembly 201, which isoperably coupled to the drive assembly, is also activated. The activateddriven assembly can cause the drive shaft 208 to rotate, which in turncauses the impeller to rotate to thereby pump blood through the patient.

FIGS. 7-8 illustrate the motor assembly 206 with one wall of the motorhousing 211 removed so that various internal components in the housing211 can be better illustrated. A motor 220 can be positioned within thehousing 211 and mounted by way of a motor mount 226. The motor 220 canoperably couple to a drive magnet 221. For example, the motor 220 caninclude an output shaft 222 that rotates the drive magnet 221. In someimplementations, the drive magnet 221 can rotate relative to the motormount 226 and the motor housing 211. Further, in some arrangements, thedrive magnet 221 can be free to translate axially between the motormount and a barrier 224. One advantage of the translating capability isto enable the drive magnet 221 and the driven magnet 204 to self-alignby way of axial translation. The barrier 224 can be mounted to the motorhousing 211 and at least partially within the cap 212 to support atleast the drive magnet 221. In other implementations, the drive assembly203 can comprise a plurality of motor windings configured to inducerotation of the drive magnet 221. In still other embodiments, motorwindings can operate directly on a driven magnet within the drivenassembly 201. For example, the windings can be activated in phases tocreate an electric field and thereby commutate the driven magnet.

In FIG. 8, the drive magnet 221 is illustrated in phantom, such that thedriven magnet 204 can be seen disposed within the drive magnet 221.Although not illustrated, the poles of the drive magnet 221 can beformed on an interior surface of the drive magnet 221, and the poles ofthe driven magnet 204 can be formed on an exterior surface of the drivenmagnet 204. As the drive magnet 221 rotates, the poles of the drivemagnet 221 can magnetically engage with corresponding, opposite poles ofthe driven magnet 204 to cause the driven magnet 204 to rotate with, orfollow, the drive magnet 221. Because the driven magnet 204 can bemechanically coupled to the drive shaft 208, rotation of the drivemagnet 221 can cause the driven magnet 204 and the drive shaft 208 torotate at a speed determined in part by the speed of the motor 220.Furthermore, when the driven magnet 204 is inserted into the drivemagnet 221, the poles of each magnet can cause the drive magnet 221 andthe driven magnet 204 to self-align. The magnetic forces between thedrive magnet 221 and the driven magnet 204 can assist in coupling thedrive assembly 203 to the driven assembly 201.

Turning to FIG. 9, a 3D perspective view of various components at theinterface between the drive assembly 203 and the driven assembly 201 isshown. Various components have been hidden to facilitate illustration ofone means to secure the drive assembly 203 to the driven assembly 201. Afirst securement device 240 is illustrated in FIG. 9. The firstsecurement device can comprise a first projection 240 a and a secondprojection 240 b. Furthermore, a locking recess 244 can be formed in thecap 212 around at least a portion of a perimeter of the opening 202. Alip 242 can also extend from the perimeter at least partially into theopening 202. As shown, the lip 242 can also extend proximally from thelocking recess 244 such that a step is formed between the locking recess244 and the lip 242. Further, a flange 246 can be coupled to or formedintegrally with the flow diverter housing 207. In certain embodiments,the he flange 246 can include a plurality of apertures 247 a, 247 b, 247c, 247 d that are configured to permit tubes and cables to passtherethrough to fluidly communicate with lumens within the flow diverter205. In some implementations, three tubes and one electrical cable canpass through the apertures 247 a-d. For example, the electrical cablecan be configured to electrically couple to a sensor within the catheterassembly 100A, e.g., a pressure sensor. The three tubes can beconfigured to carry fluid to and from the catheter assembly 100A. Forexample, a first tube can be configured to carry infusate into thecatheter assembly 100A, a second tube can be configured to transportfluids to the pressure sensor region, and the third tube can beconfigured to transport waste fluid out of the catheter assembly 100A.Although not illustrated, the tubes and cable(s) can pass through theapertures 247 a-d of the flange 246 and can rest against the motorhousing 211. By organizing the routing of the tubes and cable(s), theapertures 247 a-d can advantageously prevent the tubes and cable(s) frombecoming entangled with one another or with other components of thecatheter pump system.

When the driven assembly 201 is inserted into the opening 202, the firstand second projections 240 a, 240 b can pass through the opening andengage the locking recess 244. In some implementations, the projections240 a, 240 b and the locking recess 244 can be sized and shaped suchthat axial translation of the projections 240 a, 240 b through theopening 202 causes a flange or tab 248 at a distal end of eachprojection 240 a, 240 b to extend over the locking recess 244. Thus, insome embodiments, once the projections 240 a, 240 b are inserted throughthe opening 202, the tabs 248 at the distal end of the projections 240a, 240 b are biased to deform radially outward to engage the lockingrecess 244 to secure the driven assembly 201 to the drive assembly 203.

Once the driven assembly 201 is secured to the drive assembly 203, theflow diverter housing 207 can be rotated relative to the motor cap 212.By permitting relative rotation between the driven assembly 201 and thedrive assembly 203, the clinician is able to position the impellerassembly 116A within the patient at a desired angle or configuration toachieve the best pumping performance. As shown in FIG. 9, however, thelip 242 can act to restrict the relative rotation between the drivenassembly 201 (e.g., the flow diverter housing 207) and the driveassembly 203 (e.g. the cap 212 and the motor housing 211). Asillustrated, the flange 246 and apertures 247 a-d can becircumferentially aligned with the projections 240 a, 240 b. Further,the lip 242 can be circumferentially aligned with the sliding member213, the track 214, and the connector 291 of the motor housing 211. Ifthe flange 246 and projections 240 a, 240 b are rotated such that theycircumferentially align with the lip 242, then the tubes and cable(s)that extend from the apertures 247 a-d may become entangled with orotherwise obstructed by the sliding member 213 and the connector 291.Thus, it can be advantageous to ensure that the sliding member 213 andthe connector 291 (or any other components on the outer surface of thehousing 211) do not interfere or obstruct the tubes and cable(s)extending out of the apertures 247 a-d of the flange 246. The lip 242formed in the cap 212 can act to solve this problem by ensuring that theflange 246 is circumferentially offset from the sliding member 213 andthe connector 291. For example, the flow diverter housing 207 can berotated until one of the projections 240 a, 240 b bears against a sideof the lip 242. By preventing further rotation beyond the side of thelip 242, the lip 242 can ensure that the flange 246 and apertures 247a-d are circumferentially offset from the sliding member 213, the track214, and the connector 291.

In one embodiment, once the catheter assembly 100A is secured to themotor housing 211, the connection between the driven assembly 201 andthe drive assembly 203 may be configured such that the drive assembly203 may not be removed from the driven assembly 201. The secureconnection between the two assemblies can advantageously ensure that themotor housing 211 is not accidentally disengaged from the catheterassembly 100A during a medical procedure. In such embodiments, both thecatheter assembly 100A and the drive assembly 203 may preferably bedisposable.

In other embodiments, however, it may be desirable to utilize are-usable drive assembly 203. In such embodiments, therefore, the driveassembly 203 may be removably engaged with the catheter assembly 100A(e.g., engaged with the driven assembly 201). For example, the lip 242may be sized and shaped such that when the drive assembly 203 is rotatedrelative to the driven assembly 201, the tabs 248 are deflected radiallyinward over the lip 242 such that the driven assembly 201 can bewithdrawn from the opening 202. For example, the lip 242 may include aramped portion along the sides of the lip 242 to urge the projections240 a, 240 b radially inward. It should be appreciated that otherrelease mechanisms are possible.

Turning to FIGS. 10A-10C, an additional means to secure the driveassembly 203 to the driven assembly 201 is disclosed. As shown in the 3Dperspective view of FIG. 10A, a locking O-ring 253 can be mounted to thebarrier 224 that is disposed within the motor housing 211 and at leastpartially within the cap 212. In particular, the locking O-ring 253 canbe mounted on an inner surface of the drive or motor housing 203surrounding the recess or opening 202 into which the driven assembly 212can be received As explained below, the locking O-ring can act as adetent mechanism and can be configured to be secured within an arcuatechannel formed in an outer surface of the driven assembly 201, e.g., inan outer surface of the flow diverter 205 in some embodiments. In otherembodiments, various other mechanisms can act as a detent to secure thedriven assembly 201 to the drive assembly 203. For example, in oneembodiment, a spring plunger or other type of spring-loaded feature maybe cut or molded into the barrier 224, in a manner similar to thelocking O-ring 253 of FIGS. 10A-10C. The spring plunger or spring-loadedfeature can be configured to engage the arcuate channel, as explainedbelow with respect to FIG. 10C. Skilled artisans will understand thatother types of detent mechanisms can be employed.

FIG. 10B illustrates the same 3D perspective of the drive assembly 203as shown in FIG. 10A, except the cap 212 has been hidden to betterillustrate the locking O-ring 253 and a second, stabilizing O-ring 255.The O-ring 255 is an example of a damper that can be provided betweenthe motor 220 and the catheter assembly 100A. The damper can provide avibration absorbing benefit in some embodiments. In other embodiment,the damper may reduce noise when the pump is operating. The damper canalso both absorb vibration and reduce noise in some embodiments. Thestabilizing O-ring 255 can be disposed within the cap 212 and can besized and shaped to fit along the inner recess forming the innerperimeter of the cap 212. The stabilizing O-ring 255 can be configuredto stabilize the cap 212 and the motor housing 211 against vibrationsinduced by operation of the motor 220. For example, as the motor housing211 and/or cap 212 vibrate, the stabilizing O-ring 255 can absorb thevibrations transmitted through the cap 212. The stabilizing O-ring 255can support the cap 212 to prevent the cap from deforming or deflectingin response to vibrations. In some implementations, the O-ring 255 canact to dampen the vibrations, which can be significant given the highrotational speeds involved in the exemplary device.

In further embodiments, a damping material can also be applied aroundthe motor 220 to further dampen vibrations. The damping material can beany suitable damping material, e.g., a visco-elastic or elastic polymer.For example, the damping material may be applied between the motor mount226 and the motor 220 in some embodiments. In addition, the dampingmaterial may also be applied around the body of the motor 220 betweenthe motor 220 and the motor housing 211. In some implementations, thedamping material may be captured by a rib formed in the motor housing211. The rib may be formed around the motor 220 in some embodiments.

Turning to FIG. 10C, a proximal end of the driven assembly 201 is shown.As explained above, the flow diverter 205 (or the flow diverter housingin some embodiments) can include an arcuate channel 263 formed in anouter surface of the flow diverter 205. The arcuate channel 263 can besized and shaped to receive the locking O-ring 253 when the flowdiverter 205 is inserted into the opening 202 of the drive assembly 203.As the flow diverter 205 is axially translated through the recess oropening 202, the locking O-ring 253 can be urged or slid over an edge ofthe channel 263 and can be retained in the arcuate channel 263. Thus,the locking O-ring 253 and the arcuate channel 263 can operate to act asa second securement device. Axial forces applied to the motor assembly206 can thereby be mechanically resisted, as the walls of the arcuatechannel 263 bear against the locking O-ring 253 to prevent the lockingo-ring 253 from translating relative to the arcuate channel 263. Invarious arrangements, other internal locking mechanisms (e.g., withinthe driven assembly 201 and/or the drive assembly 203) can be providedto secure the driven and drive assemblies 201, 203 together. Forexample, the driven magnet 204 and the drive magnet 221 may beconfigured to assist in securing the two assemblies together, inaddition to aligning the poles of the magnets. Other internal lockingmechanisms may be suitable.

FIG. 10C also illustrates a resealable member 266 disposed within theproximal end portion of the driven assembly 201, e.g., the proximal endof the catheter assembly 100A as shown in FIG. 4. As in FIG. 4, theproximal guidewire opening 237 can be formed in the resealable member266. As explained above with respect to FIG. 4, the guidewire 235 can beinserted through the proximal guidewire opening 237 and can bemaneuvered through the patient's vasculature. After guiding theoperative device of the pump to the heart, the guidewire 235 can beremoved from the catheter assembly 100A by pulling the guidewire 235 outthrough the proximal guidewire opening 237. Because fluid may beintroduced into the flow diverter 205, it can be advantageous to sealthe proximal end of the flow diverter 205 to prevent fluid from leakingout of the catheter assembly 100A. The resealable member 266 cantherefore be formed of an elastic, self-sealing material that is capableof closing and sealing the proximal guidewire opening 237 when theguidewire 235 is removed. The resealable member can be formed of anysuitable material, such as an elastomeric material. In someimplementations, the resealable member 266 can be formed of any suitablepolymer, e.g., a silicone or polyisoprene polymer. Skilled artisans willunderstand that other suitable materials may be used.

FIG. 11 illustrates yet another embodiment of a motor assembly 206Acoupled to a catheter assembly. In FIG. 11, a flow diverter is disposedover and coupled to a catheter body 271 that can include a multi-lumensheath configured to transport fluids into and away from the catheterassembly. The flow diverter 205A can provide support to the catheterbody 271 and a drive shaft configured to drive the impeller assembly.Further, the motor assembly 206A can include a motor 220A that has ahollow lumen therethrough. Unlike the embodiments disclosed in FIGS.4-10C, the guidewire 235 may extend through the proximal guidewireopening 237A formed proximal to the motor 220A, rather than between themotor 220A and the flow diverter 205A. A resealable member 266A may beformed in the proximal guidewire opening 237A such that the resealablemember 266A can close the opening 237A when the guidewire 235 is removedfrom the catheter assembly. A rotary seal 273 may be disposed inside alip of the flow diverter 205A. The rotary seal 273 may be disposed overand may contact a motor shaft extending from the motor 220A. The rotaryseal 273 can act to seal fluid within the flow diverter 205A. In someembodiments, a hydrodynamic seal can be created to prevent fluid frombreaching the rotary seal 273.

In the implementation of FIG. 11, the motor 220A can be permanentlysecured to the flow diverter 205A and catheter assembly. Because theproximal guidewire opening 237 is positioned proximal the motor, themotor 220A need not be coupled with the catheter assembly in a separatecoupling step. The motor 220A and the catheter assembly can thus bedisposable in this embodiment. The motor 220A can include an outputshaft and rotor magnetically coupled with a rotatable magnet in the flowdiverter 205A. The motor 220A can also include a plurality of windingsthat are energized to directly drive the rotatable magnet in the flowdiverter 205A.

FIGS. 12A-12B illustrate another embodiment of a motor coupling having adriven assembly 401 and a drive assembly 403. Unlike the implementationsdisclosed in FIGS. 4-10C, however, the embodiment of FIGS. 12A-12B caninclude a mechanical coupling disposed between an output shaft of amotor and a proximal end of a flexible drive shaft or cable. Unlike theimplementations disclosed in FIG. 11, however, the embodiment of FIGS.12A-12B can include a guidewire guide tube that terminates at a locationdistal to a motor shaft 476 that extends from a motor 420. As best shownin FIG. 12B, an adapter shaft 472 can operably couple to the motor shaft476 extending from the motor 420. A distal end portion 477 of theadapter shaft 472 can mechanically couple to a proximal portion of anextension shaft 471 having a central lumen 478 therethrough. As shown inFIG. 12B, one or more trajectories 473 can be formed in channels withina motor housing 475 at an angle to the central lumen 478 of theextension shaft 471. The motor housing 475 can enclose at least theadapter shaft 472 and can include one or more slots 474 formed through awall of the housing 475.

In some implementations, a guidewire (not shown in FIG. 12B) may passthrough the guidewire guide tube from the distal end portion of thecatheter assembly and may exit the assembly through the central lumen478 near the distal end portion 477 of the adapter shaft 472 (or,alternatively, near the proximal end portion of the extension shaft471). In some embodiments, one of the extension shaft 471 and theadapter shaft 472 may include a resealable member disposed therein toreseal the lumen through which the guidewire passes, as explained above.In some embodiments, the extension shaft 471 and the adapter shaft 472can be combined into a single structure. When the guidewire exits thecentral lumen 478, the guidewire can pass along the angled trajectories473 which can be formed in channels and can further pass through theslots 474 to the outside environs. The trajectories 473 can follow fromangled ports in the adapter shaft 472. A clinician can thereby pull theguidewire through the slots 474 such that the end of the guidewire caneasily be pulled from the patient after guiding the catheter assembly tothe heart chamber or other desired location. Because the guidewire mayextend out the side of the housing 475 through the slots, the motorshaft 476 and motor 420 need not include a central lumen for housing theguidewire. Rather, the motor shaft 476 may be solid and the guidewirecan simply pass through the slots 474 formed in the side of the housing475.

Furthermore, the drive assembly 403 can mechanically couple to thedriven assembly 401. For example, a distal end portion 479 of theextension shaft 471 may be inserted into an opening in a flow diverterhousing 455. The distal end portion 479 of the extension shaft 471 maybe positioned within a recess 451 and may couple to a proximal end of adrive cable 450 that is mechanically coupled to the impeller assembly. Arotary seal 461 may be positioned around the opening and can beconfigured to seal the motor 420 and/or motor housing 475 from fluidwithin the flow diverter 405. Advantageously, the embodiments of FIGS.12A-B allow the motor 420 to be positioned proximal of the rotary sealin order to minimize or prevent exposing the motor 420 to fluid that mayinadvertently leak from the flow diverter. It should be appreciated thatthe extension shaft 471 may be lengthened in order to further isolate orseparate the motor 420 from the fluid diverter 405 in order to minimizethe risk of leaking fluids.

III. Examples of Guidewire Guides and Distal Tip Members

Turning to FIG. 13, further features that may be included in variousembodiments are disclosed. FIG. 13 illustrates a distal end portion 300of a catheter assembly, such as the catheter assembly 100A describedabove. As shown a cannula housing 302 can couple to a distal tip member304. The distal tip member 304 can be configured to assist in guidingthe operative device of the catheter assembly, e.g., an impellerassembly (which can be similar to or the same as impeller assembly116A), along the guidewire 235. The exemplary distal tip member 304 isformed of a flexible material and has a rounded end to prevent injury tothe surrounding tissue. If the distal tip member 304 contacts a portionof the patient's anatomy (such as a heart wall or an arterial wall), thedistal tip member 304 will safely deform or bend without harming thepatient. The tip can also serve to space the operative device away fromthe tissue wall. In addition, a guidewire guide tube 312, discussedabove with reference to FIG. 4, can extend through a central lumen ofthe catheter assembly. Thus, the guidewire guide tube 312 can passthrough the impeller shaft (not shown, as the impeller is locatedproximal to the distal end portion 300 shown in FIG. 13) and a lumenformed within the distal tip member 304. In the embodiment of FIG. 13,the guidewire guide tube 312 may extend distally past the distal end ofthe distal tip member 304. As explained above, in various embodiments,the clinician can introduce a proximal end of the the guidewire into thedistal end of the guidewire guide tube 312, which in FIG. 13 extendsdistally beyond the tip member 304. Once the guidewire 235 has beeninserted into the patient, the guidewire guide tube 312 can be removedfrom the catheter assembly in some implementations.

The distal tip member 304 can comprise a flexible, central body 306, aproximal coupling member 308, and a rounded tip 310 at the distal end ofthe tip member 304. The central body 306 can provide structural supportfor the distal tip member 304. The proximal coupling member 308 can becoupled to or integrally formed with the central body 306. The proximalcoupling member 308 can be configured to couple the distal end of thecannula housing 302 to the distal tip member 304. The rounded tip 310,also referred to as a ball tip, can be integrally formed with thecentral body 306 at a distal end of the tip member 304. Because therounded tip 310 is flexible and has a round shape, if the tip member 304contacts or interacts with the patient's anatomy, the rounded tip 310can have sufficient compliance so as to deflect away from the anatomyinstead of puncturing or otherwise injuring the anatomy. As comparedwith other potential implementations, the distal tip member 304 canadvantageously include sufficient structure by way of the central body306 such that the tip member 304 can accurately track the guidewire 235to position the impeller assembly within the heart. Yet, because the tipmember 304 is made of a flexible material and includes the rounded tip310, any mechanical interactions with the anatomy can be clinically safefor the patient.

One potential problem with the embodiment of FIG. 13 is that it can bedifficult for the clinician to insert the guidewire into the narrowlumen of the guidewire guide tube 312. Since the guidewire guide tube312 has a small inner diameter relative to the size of the clinician'shands, the clinician may have trouble inserting the guidewire into thedistal end of the guidewire guide tube 312, which extends past thedistal end of the tip member 304 in FIG. 13. In addition, when theclinician inserts the guidewire into the guidewire guide tube 312, thedistal edges of the guidewire guide tube 312 may scratch or partiallyremove a protective coating applied on the exterior surface of theguidewire. Damage to the coating on the guidewire may harm the patientas the partially uncoated guidewire is passed through the patient'svasculature. Accordingly, it can be desirable in various arrangements tomake it easier for the clinician to insert the guidewire into the distalend of the catheter assembly, and/or to permit insertion of theguidewire into the catheter assembly while maintaining the protectivecoating on the guidewire.

Additionally, as explained herein, the cannula housing 302 (which mayform part of an operative device) may be collapsed into a storedconfiguration in some embodiments such that the cannula housing isdisposed within an outer sheath. When the cannula housing 302 isdisposed within the outer sheath, a distal end or edge of the outersheath may abut the tip member 304. In some cases, the distal edge ofthe outer sheath may extend over the tip member 304A, or the sheath mayhave an outer diameter such that the distal edge of the outer sheath isexposed. When the sheath is advanced through the patient's vasculature,the distal edge of the outer sheath may scratch, scrape, or otherwiseharm the anatomy. There is a therefore a need to prevent harm to thepatient's anatomy due to scraping of the distal edge of the sheathagainst the vasculature.

FIG. 14 is a side cross-sectional view of a distal tip member 304Adisposed at a distal end 300A of the catheter assembly, according toanother embodiment. Unless otherwise noted, the reference numerals inFIG. 14 may refer to components similar to or the same as those in FIG.13. For example, as with FIG. 13, the distal tip member 304A can coupleto a cannula housing 302A. The distal tip member 304A can include aflexible, central body 306A, a proximal coupling member 308A, and arounded tip 310A at the distal end of the tip member 304A. Furthermore,as with FIG. 13, a guidewire guide tube 312A can pass through thecannula housing 302A and a lumen passing through the distal tip member304A.

However, unlike the embodiment of FIG. 13, the central body 306A caninclude a bump 314 disposed near a proximal portion of the tip member304A. The bump 314 illustrated in FIG. 14 may advantageously prevent theouter sheath from scraping or scratching the anatomy when the sheath isadvanced through the patient's vascular system. For example, when thecannula housing 302A is disposed within the outer sheath, the sheathwill advance over the cannula housing 302A such that the distal edge orend of the sheath will abut or be adjacent the bump 314 of the tipmember 304A. The bump 314 can act to shield the patient's anatomy fromsharp edges of the outer sheath as the distal end 300A is advancedthrough the patient. Further, the patient may not be harmed when thebump 314 interact with the anatomy, because the bump 314 includes arounded, smooth profile. Accordingly, the bump 314 in FIG. 14 mayadvantageously improve patient outcomes by further protecting thepatient's anatomy.

Furthermore, the guidewire guide tube 312A of FIG. 14 does not extenddistally past the end of the tip member 306A. Rather, in FIG. 14, thecentral lumen passing through the tip member 304A may include a proximallumen 315 and a distal lumen 313. As shown in FIG. 14, the proximallumen 315 may have an inner diameter larger than an inner diameter ofthe distal lumen 313. A stepped portion or shoulder 311 may define thetransition between the proximal lumen 315 and the distal lumen 313. Asillustrated in FIG. 14, the inner diameter of the proximal lumen 315 issized to accommodate the guidewire guide tube 312A as it passes througha portion of the tip member 304A. However, the inner diameter of thedistal lumen 313 in FIG. 14 is sized to be smaller than the outerdiameter of the guidewire guide tube 312A such that the guidewire guidetube 312A is too large to pass through the distal lumen 313 of the tipmember 304A. In addition, in some embodiments, the thickness of theguidewire guide tube 312A may be made smaller than the height of thestepped portion or shoulder 311, e.g., smaller than the differencebetween the inner diameter of the proximal lumen 315 and the innerdiameter of the distal lumen 313. By housing the guidewire guide tube312A against the shoulder 311, the shoulder 311 can protect the outercoating of the guidewire when the guidewire is inserted proximally fromthe distal lumen 313 to the proximal lumen 315.

The embodiment illustrated in FIG. 14 may assist the clinician ininserting the guidewire (e.g., the guidewire 235 described above) intothe distal end 300A of the catheter assembly. For example, in FIG. 14,the guidewire guide tube 312A may be inserted through the central lumenof the catheter assembly. For example, the guidewire guide tube 312A maypass distally through a portion of the motor, the catheter body, theimpeller assembly and cannula housing 302A, and through the proximallumen 315 of the tip member 304A. The guidewire guide tube 312A may beurged further distally until the distal end of the guidewire guide tube312A reaches the shoulder 311. When the distal end of the guidewireguide tube 312A reaches the shoulder 311, the shoulder 311 may preventfurther insertion of the guidewire guide tube 312 in the distaldirection. Because the inner diameter of the distal lumen 313 is smallerthan the outer diameter of the guidewire guide tube 312A, the distal endof the guidewire guide tube 312A may be disposed just proximal of theshoulder 311, as shown in FIG. 14.

The clinician may insert the proximal end of the guidewire (such as theguidewire 235 described above) proximally through the distal lumen 313passing through the rounded tip 310A at the distal end of the tip member304A. Because the tip member 304A is flexible, the clinician can easilybend or otherwise manipulate the distal end of the tip member 304A toaccommodate the small guidewire. Unlike the guidewire guide tube 312A,which may be generally stiffer than the tip member 304A, the clinicianmay easily deform the tip member 304A to urge the guidewire into thedistal lumen 313. Once the guidewire is inserted in the distal lumen313, the clinician can urge the guidewire proximally past the steppedportion 311 and into the larger guidewire guide tube 312A, which may bepositioned within the proximal lumen 315. Furthermore, since mostcommercial guidewires include a coating (e.g. a hydrophilic orantomicrobial coating, or PTFE coating), the exemplary guide tube andshoulder advantageously avoid damaging or removing the coating. When thewall thickness of the guidewire guide tube 312A is less than the heightof the step or shoulder 311, the shoulder 311 may substantially preventthe guidewire guide tube 312A from scraping the exterior coating off ofthe guidewire. Instead, the guidewire easily passes from the distallumen 313 to the proximal lumen 315. The guidewire may then be urgedproximally through the impeller and catheter assembly until theguidewire protrudes from the proximal end of the system, such as throughthe proximal guidewire opening 237 described above with reference toFIG. 4.

IV. Examples of Access Ports

The guidewire guide tubes 312, 312A described above with reference toFIGS. 13 and 14 can be configured to receive a guidewire for positioningan impeller assembly 316A and cannula housing 302A in the heart of apatient, e.g., across the aortic valve of the patient. As explained withreference to FIGS. 13 and 14, the guidewire guide tubes 312, 312A may beremoved at some point after the guidewire is inserted within theguidewire guide tube 312, 312A. For example, the guidewire guide tube312, 312A may be removed before the catheter assembly is insertedthrough the vascular system of the patient, e.g., by a modifiedSeldinger technique. One reason for removing the guidewire guide tubes312, 312A before insertion is that the guidewire guide tubes 312, 312Amay be too stiff to safely and reliably traverse the anatomy. Forexample, the guidewire guide tubes 312, 312A may have a stiffness thatdoes not easily bend around the aortic arch during insertion. Thus, forremovable guidewire guides 312, 312A, the guidewire can be insertedthrough the guidewire guide tube 312 or 312A, and the guidewire guidetube 312, 312A can be removed from the catheter assembly before thecatheter assembly is inserted into the anatomy and to the heart.

However, in some arrangements, it may be advantageous to provide atubular access port or access channel that provides access to the heartduring treatment. The access channel can comprise a body having a lumentherethrough, such as a tube or similar structure. In some embodiments,the access channel can comprise a guidewire guide configured to remainin the catheter pump (and therefore the patient's vascular system)during treatment. In some embodiments, the guidewire guide may benon-removable or permanent; in other embodiments, the guidewire guidecan be removed by the clinician if required or desired. In somearrangements, the guidewire guide may be fixed or secured to thecatheter assembly such that the guidewire guide remains coupled to thecatheter assembly during insertion and during the treatment procedure(e.g., when the impeller rotates at operational speeds). Thus, in someembodiments, a guidewire can be inserted through the guidewire guide asexplained above. The guidewire may be advanced through the vasculatureof the patient to the desired treatment region (e.g., the left ventriclein some embodiments). The catheter assembly with the guidewire guide maypass over the guidewire through the vasculature of the patient toposition the impeller assembly and cannula in a chamber of the heart.The guidewire can be removed before operation of the pump, but theguidewire guide may remain disposed in the catheter assembly during thetreatment procedure.

Advantageously, an access channel (e.g., a tube, such as a guidewireguide, comprising an internal channel) can give the clinician access tothe heart during treatment. For example, if the cannula and impellerassembly become misaligned during treatment, the clinician can simplyreinsert the guidewire through the access channel (e.g., a guidewireguide), and can move the catheter assembly to the desired position. Inaddition, one or more sensors can be disposed through the access channelto measure and transmit various fluid properties (e.g., pressure,temperature, flow rate, concentration, etc.) to a console or systemcontroller. The access channel can also enable delivery of variouschemicals and/or medications to the heart during a treatment procedure.Such medications may include, but are not limited to, antithrombotics,antiplatelets, anticoagulants (e.g. heparin or warfarin), superaspirins,thrombolytics, inotropes, vasopressors and vasodilators, diuretics, andanitretrovirals. The exemplary structure described above advantageouslyallows easy delivery of medication to the left ventricle or rightventricle, whichever the case may be, without requiring a separatecatheter.

In some embodiments, the access channel can be similar to the guidewireguide 312A shown in FIG. 14. For example, an access channel 312B (e.g.,a guidewire guide), also shown in FIG. 14, may extend distally theimpeller assembly 316A and through at least a portion of the impellerand the tip member 304A. In particular, the access channel 312B can bedisposed through a lumen of the catheter body 84 from a proximal portionof the catheter body 84, through a shaft of the impeller and can passdistal the impeller to the tip member 304A. However, unlike theguidewire guide 312A, which is removable, the access channel 312B mayremain inside the catheter assembly during a treatment procedure. To atleast partially enable the use of an access channel 312B (e.g., aguidewire guide that can remain in the patient and catheter assemblyduring operation), the access channel 312B may have a bending stiffnesssufficiently low such that the access channel 312 (which may comprise atubular structure having an internal channel or lumen) can safely andreliably traverse curves in the vasculature, e.g., the aortic arch. Forexample, the access channel 312B may comprise nitinol, an alloycomprising nickel and titanium, in various embodiments. The use ofnitinol in the access channel 312B can allow the access channel 312B toremain in the anatomy during insertion and operation of the catheterassembly.

In particular, a guidewire can be inserted through the access channel312B (e.g., a guidewire guide), as described above with respect toguidewire guide 312A. However, unlike the guidewire guide 312A describedabove, the access channel 312B can remain disposed in the catheterassembly as the catheter assembly is advanced through the vascularsystem of the patient. Further, the access channel 312B can remaindisposed in the catheter assembly while the impeller rotates to pumpblood through the catheter assembly. In some embodiments, the accesschannel 312B (e.g., a stationary guidewire guide) can remainsubstantially stationary relative to the impeller, such that theimpeller rotates about the access channel 312B.

During operation of the impeller, the clinician may use the accesschannel 312B to access the heart. As explained above, the impellerassembly 92 may become misaligned during a procedure. To re-align and/orreposition the impeller assembly 92, the clinician may reinsert aguidewire through the access channel 312B, and can move the impellerassembly 92 proximally or distally relative to the guidewire toreposition the impeller assembly 92. Furthermore, the clinician maydeliver medications or chemicals through the access channel 312B duringa treatment. Various types of sensors may also pass through the accesschannel 312B to measure properties of blood flowing through the pump,such as pressure, flow rate, temperature, chemical or biologicalcomposition, etc.

FIG. 15 is a side view of an impeller assembly 316A having a cannulahousing 302A, an impeller 317 disposed in the cannula housing 302A, anda tip member 304A. The components shown in FIG. 15 may be the same as orsimilar to the components illustrated in FIG. 14. A distal bearingsupport 318 can be disposed distal the impeller 317 and can provideradial support to the cannula housing 302A to maintain a tip gap betweena free end of an impeller blade and an interior surface of the cannulahousing 302A. Additional details of the distal bearing support 318 canbe found throughout U.S. Patent Publication No. 2013/0303970 A1, andadditional details of the impeller 317 can be found throughout U.S.Patent Publication No. 2013/0303830 A1, each of which is incorporated byreference herein in its entirety and for all purposes. A tubular accesschannel 312B or 312C can be disposed through the impeller 317 (e.g.,through an impeller shaft to which the impeller 317 is coupled) and canpass distal the impeller 317. The access channel 312B, 312C can extendbetween the impeller 317 and the tip member 304A. The distal end of theaccess channel 312B, 312C can couple to the tip member 304A as shown inFIG. 14. The catheter assembly (e.g. including the impeller assembly316A) can be configured such that when the impeller 317 rotates, theaccess channel 312B, 312C remains substantially stationary, e.g., theaccess channel 312B, 312C does not rotate with the impeller 317.

FIG. 16 is a side cross-sectional view of an access channel 312Cdisposed at a distal end 300A of the catheter assembly and configured toremain in the catheter assembly during treatment, according to anotherembodiment. As with the access channel 312B of FIG. 14, the accesschannel 312C may be configured to remain within the catheter assemblyduring insertion and operation of the impeller assembly 316A. Forexample, the access channel 312C can comprise nitinol, which may enablethe tubular access channel 312C to traverse the anatomy (e.g., theaortic arch) to the heart.

The access channel 312C can include one or more windows 337A, 337Bformed through a side wall of the access channel 312C. The windows 337A,337B can provide fluid communication between an internal channel of theaccess channel 312C and blood flowing through the impeller assembly 92.For example, in some embodiments, a sensor connector 335 can passthrough the channel of the access channel 312C, and a sensor tip 336 ata distal end of the connector 335 can be disposed adjacent a window337A, 337B (e.g., window 337B as shown in FIG. 16). In some embodiments,the sensor tip 336 can comprise a pressure sensor for measuring thepressure of the blood flowing past the window 337A, 337B. For example,the pressure sensor can comprise a suitable fiber optic pressure sensor.

In other arrangements, the sensor tip 336 can be advanced through theaccess channel 312C to a location near a distal opening 339 of theaccess channel 312C. The distal opening 339 can provide fluidcommunication between the sensor tip 316 and distal opening 338 of thetip member 304A. For example, the sensor tip 316 can measure propertiesof the blood through the distal opening 339 of the access channel 312Cand the distal opening 338 of the tip member 304A. In still otherarrangements, the clinician can supply a chemical or medication to theheart during treatment by passing the chemical or medication through theinternal channel of the tube 312C and into the patient by way of thewindow 337A or 337B or the distal openings 339, 338 of the tube 312C andtip member 304A, respectively. Although the windows 337A, 337B are shownas distal the impeller in FIG. 16, it should be appreciated thatadditional windows may be provided at other locations along the accesschannel 312B, 312C, e.g., proximal the impeller. Providing multiplewindows in the access channel can enable access to the anatomy atvarious locations along the catheter assembly. For example, variousfluid properties, such as pressure, may be measured at multiple pointsto map the properties along the catheter assembly.

FIGS. 17A and 17B are images of a proximal portion of a tubular accesschannel, which may be similar to the access channel 312B or 312C shownin FIGS. 14-16. The access channel 312B, 312C can extend from theimpeller assembly 316A proximally through the elongate catheter body 84and can exit proximally from the catheter assembly through the motorhousing 211. In some embodiments, the access channel 312B, 312C can exitthrough one of the channels 247 a-d, or indeed through any suitableopening near the proximal portion of the catheter assembly. Toaccommodate a central, tubular access channel 312B, 312C, the motorhousing 211 can comprise a proximal opening 341 formed through aproximal end portion of the housing 211. The motor can include hollowmotor and/or drive shafts to accommodate the access channel 312B, 312C.As shown in FIG. 17A, the access channel 312B, 312C can extendproximally through the proximal opening 341 of the motor housing 211. Inaddition, to accommodate the access channel 312B, 312C, the barrier 224described above may also have a barrier opening 342 through which thetubular access channel 312B, 312C can pass.

The access channel 312B, 312C disclosed herein can have wallssufficiently thick to support the tube 312B, 312C as it traverses theanatomy, e.g., the aortic arch. For example, the tube 312B, 312C cancomprise a nitinol tube having a wall thickness of about 0.020″×0.025″,or about 0.020″×0.023″, in various arrangements. The access channel312B, 312C can comprise a super-elastic material. In addition, one ormore fluid seals can be disposed along the guidewire guide 312B, 312C toprevent fluid from flowing out proximally of the catheter assembly. Theseal(s) can be disposed near the impeller assembly 316A in somearrangements, while in other arrangements, the seal(s) can be disposedin the catheter body 84.

Accordingly, as explained herein, a tubular access channel can permitthe clinician to have access to the heart during a treatment procedure,e.g. while the impeller is rotating. During a treatment procedure, forexample, the clinician may insert a guidewire through an access channel(e.g., a guidewire guide tube). The access channel can be disposed in acatheter pump comprising a catheter body and an impeller assemblycoupled to a distal portion of the catheter body. The clinician canadvance the guidewire to a treatment location in a patient, such as aleft ventricle of the patient's heart. The clinician can advance atleast the impeller assembly, the catheter body, and the tubular accesschannel along the guidewire to position the impeller assembly at thetreatment location. The clinician can activate the impeller assembly topump blood while maintaining the access channel in the catheter pump.

The clinician can remove the guidewire from the patient beforeactivating the impeller assembly. In some embodiments, the clinician caninsert a sensor through the access channel and can advance the sensor toa location near the treatment location. The sensor can measure aproperty of the pumped blood. In some arrangements, the impellerassembly may become misaligned from the desired treatment location. Theclinician can re-align the impeller assembly by deactivating theimpeller assembly and inserting a second guidewire through the accesschannel while the access channel remains in the patient. The cliniciancan reposition the impeller assembly using the second guidewire. In someembodiments, the clinician can dispense a chemical or medication to thetreatment location through the access channel. Advantageously, theaccess channel can provide the clinician with access to the heart duringa treatment procedure.

Although the inventions herein have been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent inventions. It is therefore to be understood that numerousmodifications can be made to the illustrative embodiments and that otherarrangements can be devised without departing from the spirit and scopeof the present inventions as defined by the appended claims. Thus, it isintended that the present application cover the modifications andvariations of these embodiments and their equivalents.

What is claimed is:
 1. A catheter pump comprising: an elongate catheterbody; an impeller assembly coupled to a distal portion of the elongatecatheter body, the impeller assembly comprising an impeller configuredto rotate during operation of the catheter pump; and an access channelextending through at least portions of the elongate catheter body andthe impeller assembly, the access channel extending distal the impellerand proximal the impeller, the access channel configured to remain inthe portions of the elongate catheter body and the impeller assemblyduring operation of the catheter pump, wherein the access channelextends through the impeller, wherein the access channel comprises aguidewire guide configured to receive a guidewire therethrough fornavigating the impeller assembly through a portion of a vascular systemof a patient.
 2. The catheter pump of claim 1, wherein the accesschannel comprises a tube.
 3. The catheter pump of claim 1, furthercomprising a guidewire configured to guide the impeller assembly to achamber of a heart.
 4. The catheter pump of claim 1, wherein the accesschannel comprises one or more windows through a side wall of the accesschannel, the window(s) providing fluid communication between a lumen ofthe access channel and blood flowing through the catheter pump.
 5. Thecatheter pump of claim 4, further comprising a cannula disposed aboutthe impeller assembly, wherein the window(s) comprise apertures in asidewall of the access channel providing fluid communication or accessbetween an internal lumen of the access channel and a volume of thecannula.
 6. The catheter pump of claim 1, wherein the access channelcomprises a distal opening, the distal opening providing fluidcommunication between a channel of the access channel and blood flowingthrough the catheter pump.
 7. The catheter pump of claim 1, furthercomprising a tip member at a distal portion of the impeller assembly,the access channel extending between the impeller and the tip member. 8.The catheter pump of claim 7, wherein the access channel passes througha portion of a lumen extending through the tip member.
 9. A catheterpump comprising: an elongate catheter body; an impeller assembly coupledto a distal portion of the elongate catheter body, the impeller assemblycomprising an impeller configured to rotate during operation of thecatheter pump; an access channel extending through at least portions ofthe elongate catheter body and the impeller assembly, the access channelextending distal the impeller and configured to remain in the portionsof the elongate catheter body and the impeller assembly during operationof the catheter pump; and a tip member at a distal portion of theimpeller assembly, the access channel extending between the impeller andthe tip member, wherein the access channel passes through a lumenextending through the tip member, wherein a distal end of the accesschannel is disposed adjacent a shoulder, the shoulder defining aninterface between a first portion of the lumen and a second portion ofthe lumen, the second portion of the lumen narrower than the firstportion of the lumen, the access channel passing through the firstportion of the lumen.
 10. The catheter pump of claim 1, wherein theaccess channel comprises a super-elastic material.
 11. The catheter pumpof claim 1, wherein the access channel comprises nitinol.
 12. A catheterpump comprising: an elongate catheter body; an impeller assembly coupledto a distal portion of the elongate catheter body, the impeller assemblycomprising an impeller configured to rotate during operation of thecatheter pump; and an access channel extending through at least portionsof the elongate catheter body and the impeller assembly, the accesschannel extending distal the impeller and configured to remain in theportions of the elongate catheter body and the impeller assembly duringoperation of the catheter pump, wherein the catheter pump is configuredsuch that the access channel does not rotate with the impeller.
 13. Thecatheter pump of claim 1, further comprising a sensor configured to beadvanced within the access channel to measure a property of bloodflowing through the catheter pump.
 14. A method of operating a catheterpump, the method comprising: advancing a guidewire to a treatmentlocation in a patient; disposing a distal end of a guidewire guide tubeover the guidewire, the guidewire guide tube disposed in a catheter pumpcomprising a catheter body and an impeller assembly coupled to a distalportion of the catheter body, the guidewire guide tube disposed distaland proximal the impeller assembly, the impeller assembly comprising animpeller, the guidewire guide tube extending through the impeller;advancing the impeller assembly, the catheter body, and the guidewireguide tube along the guidewire to position the impeller assembly at thetreatment location; and activating the impeller assembly to pump bloodwhile maintaining the guidewire guide tube in the catheter pump.
 15. Themethod of claim 14, further comprising removing the guidewire from thepatient before activating the impeller assembly.
 16. The method of claim14, further comprising inserting a sensor through the guidewire guidetube and advancing the sensor to a location near the treatment location.17. The method of claim 16, further comprising measuring a property ofthe pumped blood using the sensor.
 18. A method of operating a catheterpump, the method comprising: advancing a guidewire to a treatmentlocation in a patient; disposing a distal end of a guidewire guide tubeover the guidewire, the guidewire guide tube disposed in a catheter pumpcomprising a catheter body and an impeller assembly coupled to a distalportion of the catheter body; advancing the impeller assembly, thecatheter body, and the guidewire guide tube along the guidewire toposition the impeller assembly at the treatment location; and activatingthe impeller assembly to pump blood while maintaining the guidewireguide tube in the catheter pump; deactivating the impeller assembly;inserting a second guidewire through the guidewire guide tube while theguidewire guide tube remains in the patient; and repositioning theimpeller assembly using the second guidewire.
 19. The method of claim14, further comprising dispensing a chemical or medication to thetreatment location through the guidewire guide tube.
 20. The catheterpump of claim 12, further comprising a sensor configured to be advancedwithin the access channel to measure a property of blood flowing throughthe catheter pump.
 21. The method of claim 12, wherein the accesschannel comprises nitinol.